Copper- versus palladium-catalyzed aromatization of 2-(methoxycarbonyl) tetralones: synthesis of methyl 1-hydroxy-2-naphthoates

Abstract

Please cite this article as: Cívicos JF, Rocha CM, Costa PRR, Nájera C, Copper-versus palladiumcatalyzed aromatization of 2-(methoxycarbonyl) tetralones: synthesis of methyl 1-hydroxy-2-naphthoates, Tetrahedron (2016),

A Radical-Based Synthesis of Lingzhiol

“…Following the route of Schemes and , 27 was carboxylated to ketoester 28 and then added to acrolein under basic conditions (Scheme ). Aldehyde 29 could be converted to alkyne 30 using the Ohira-Bestmann reagent.…”

Synthesis of 1‐Naphthol‐based Unsymmetrical Triarylmethanes: Heck‐type Desulfitative Reaction of Arylsulfonyl Chlorides with Tetralone‐derived Chalcones

“…Based on the observed products and in concurrence with mechanism proposed in the literature for the desulfitative coupling/conjugate addition of arylsulfonyl chloride with enones, [6] a plausible reaction pathway for the formation of 1‐naphthol‐based unsymmetrical triarylmethanes 7 in the Pd‐catalyzed Heck‐type desulfitative reaction/conjugate addition of arylsulfonyl chlorides 6 with tetralone‐derived chalcones 5 is proposed (Scheme 5). In concurrence with the proposed mechanism for the reactions involving the Pd‐catalyzed aromatization of tetralones into 1‐naphthols, [7a–f] it is proposed that after the initial Heck coupling step with the palladium species ( III ), [6] the formation of the O ‐Pd enolate 10 a in equilibrium with C ‐Pd enolate 10 b occurs. The intermediate 10 b undergoes the β ‐hydride elimination to afford the unsaturated α ‐tetralone intermediates 10 c or 10 d , which then affords the 1‐naphthol derivative 7 via the tautomerization process [7a] .…”

“…In concurrence with the proposed mechanism for the reactions involving the Pd‐catalyzed aromatization of tetralones into 1‐naphthols, [7a–f] it is proposed that after the initial Heck coupling step with the palladium species ( III ), [6] the formation of the O ‐Pd enolate 10 a in equilibrium with C ‐Pd enolate 10 b occurs. The intermediate 10 b undergoes the β ‐hydride elimination to afford the unsaturated α ‐tetralone intermediates 10 c or 10 d , which then affords the 1‐naphthol derivative 7 via the tautomerization process [7a] . While at this stage an exact role of PhI[OAc] 2 is not known and it is believed that it may be functioning as a promoter and/or it may be facilitating the reaction with the involvement of Pd(II)–Pd(IV) species in the catalytic cycle [14–16] .…”

“… Proposed mechanism for the formation of 1‐naphthol‐based unsymmetrical triarylmethanes 7 from 5 [6c,7a–f,14–16] …”